Heretofore, there is an inner rotor electric motor in which a rotor is coaxially disposed at the center of a stator. FIG. 3 illustrates the configuration of an electric motor as a conventional art, where (a) is a plan view and (b) is a cross section view. FIGS. 3(a) and (b) illustrate a radial air gap electric motor. The radial air gap electric motor includes a rotor 12 formed of a cylindrical permanent magnet and disposed on the inner peripheral side and a doughnut-shaped stator 13 disposed on the outer peripheral side with respect to a rotating shaft 11.
As illustrated in FIG. 3(b), a bearing portion 14 for securing the rotating shaft 11 includes a ball bearing 141 and a bearing housing 142. The ends of the bearing housing and the entire annular stator 13 are integrally molded and secured with a synthetic resin 15. The rotating shaft 11 integrated with the rotor 12 and the ball bearing 141 press-fit in the rotating shaft 11 are inserted into the bearing housing 142. Thus, a magnet portion 121 of the rotor 12 is disposed proximate to and opposite the inner side of the annular stator 13. In this state, as illustrated in FIGS. 3(a) and (b), a board 16 is disposed from above. On the board 16, there are formed a wiring pattern for supplying electric power to a control IC 20 disposed on the board 16, and a wiring pattern for supplying electric power to the windings of the stator 13 via the control IC 20. To the board 16, lead wires 18 bundled by a bushing 17 secured on an outer peripheral portion above the stator 13 are connected by soldering or the like. The lead wires 18 are used for supplying electric power to the electric motor.
Hence, there is known an electric motor having windings connected to each other using a board provided with cut-outs at edges thereof and formed in a substantially rectangular shape (see, for example, Patent Literature 1). FIG. 3 illustrates the electric motor using such a board with a substantially rectangular shape.
PATENT LITERATURE 1: JP 08-223842 A